AB0352 FREQUENCY, CLINICAL AND FUNCTIONAL IMPACT OF FOOT INVOLVEMENT IN RHEUMATOID ARTHRITIS
Authors: C. Pinto Oliveira, S. F. Azevedo, S. P. Silva, A. R. Prata, A. Barcelos
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Rheumatoid Arthritis (RA) is a chronic inflammatory disorder affecting the joint synovium. Foot involvement is frequent throughout the disease course<sup>[1]</sup>. However, definition of foot involvement differs, with some scientific works using patient reported outcomes, especially pain, rather than arthritis detected by clinical examination or ultrasound<sup>[2,3]</sup>. <h3>Objectives</h3> Primary – to study the frequency and pattern of foot involvement in RA's patients. Secondary – to compare patients with or without foot involvement concerning sociodemographic, clinical, radiographic and laboratorial characteristics. <h3>Methods</h3> Single center, retrospective study including patients evaluated in our center with a diagnosis of RA, between June-December, 2022. All patients fulfilled the 2010 ACR/EULAR classification criteria for RA. Patient records were searched for sociodemographic, clinical, laboratorial, and radiographic data. Multimorbidity was defined as the coexistence of 2 or more comorbidities. Patients were divided into two groups, according to the presence/absence of cumulative foot involvement, defined as the presence of clinical arthritis or synovitis in ultrasound. Descriptive analysis used mean, median, standard deviation, and interquartile range for continuous data, as well as frequency counts and percentages for categorical variables. A statistical analysis was performed, with a statistically significant <i>p</i>-value ≤ 0.05. The two groups of patients (with/without foot involvement) were compared using parametric and non-parametric tests for continuous variables, and Chi-squared test for categorical variables. <h3>Results</h3> 110 patients were enrolled, with a mean age of 62.97 ± 13.81 years. 84 patients were women (76.36%). Cumulative foot involvement was found in 71 patients (64.55%). The forefoot was the most frequently affected area (69.01% of the patients with foot involvement, <i>n</i>=49), followed by the tibiotarsal joint (53.52%; <i>n=</i>38), the mid foot (12.68%; <i>n</i>=9) and the hindfoot (11.27%; <i>n</i>=8). Patients with foot involvement were more likely to receive a biologic disease modifying anti-rheumatic drug (<i>p</i> &lt;0.05). We found no statistically significant differences between patients with or without foot involvement regarding gender, age at diagnosis, disease duration, rheumatoid factor or anti-citrullinated protein antibodies positivity, bone erosions, multimorbidity, inflammatory markers levels, number of tender or swollen joints at last evaluation, mean Disease Activity Score (DAS)28-C-reactive protein (CRP) and DAS28-erythrocyte sedimentation rate (ESR) or Health Assessment Questionnaire Disability Index Score (HAQ-DI). <h3>Conclusion</h3> In our study, objective foot involvement in RA was frequent and associated with higher probability of biological therapy. However, it did not correlate with poor prognosis factors<sup>[4]</sup> such as seropositivity, bone erosions or high disease activity measured by DAS28-CRP and DAS28-ESR. We found no higher levels of disability (as measured by the HAQ-DI) in patients with RA involving the foot. Studies with greater sample sizes are paramount to better comprehend the clinical and functional impact of foot involvement in RA, using clearer definitions of the former. <h3>References</h3> [1] Grondal, Lollo, et al. "The foot: still the most important reason for walking incapacity in rheumatoid arthritis: distribution of symptomatic joints in 1,000 RA patients." <i>Acta orthopaedica</i> 79.2 (2008): 257-261. [2] Fazaa, Alia, et al. "Assessment of the functional impact of foot involvement in patients with Rheumatoid Arthritis." <i>The Foot</i> (2022): 101907. [3] Khan, Sajid Ali, et al. "Foot Involvement as the First Manifestation in Rheumatoid Arthritis Patients in Lahore." <i>Cureus</i> 13.5 (2021). [4] Smolen, Josef S., et al. "EULAR recommendations for the management of rheumatoid arthritis with synthetic and biological disease-modifying antirheumatic drugs: 2022 update." <i>Annals of the Rheumatic Diseases</i> 82.1 (2023): 3-18. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.